Headspace gas analyzer/residual oxygen analyzer is a device that analyzes sample characteristics by detecting the top gas components in a closed container, and is widely used in quality control in fields such as food, medicine, and chemical engineering. The debugging process involves multiple steps such as equipment installation, parameter setting, calibration, and sample testing, and must be strictly carried out in accordance with operating standards to ensure the accuracy and reliability of data.

　　The following is the detailed process and key points for debugging headspace gas analyzer/residual oxygen analyzer.

1、 Preparation work before debugging

1. Environmental requirements

1) Ensure a clean and dry laboratory environment, avoiding dust, corrosive gases, or strong electromagnetic interference.

2) Control the room temperature at 20-25 ℃ and humidity at 40% -60% to avoid temperature fluctuations affecting sensor stability.

3) Prepare a stable power supply (such as UPS power supply) to avoid voltage fluctuations causing damage to precision electronic components.

2. Equipment inspection

1) Check if the instrument accessories are complete, including the host, sampling needle, sensor module, standard gas cylinder, data cable, etc.

2) Check if the pneumatic system (such as pumps, valves, pipelines) is sealed to prevent detection errors caused by air leakage.

3) Confirm that the sensor type (such as electrochemical sensor, infrared sensor, PID sensor) matches the target gas.

3. Sample preparation

1) Prepare standard gases (such as N?, O?)? 、 CO?, etc.), with a concentration covering the range to be measured, used for calibrating instruments.

2) The test sample needs to be well sealed, with a reasonable ratio of headspace volume to container volume (usually the headspace volume accounts for 20% -50% of the total container volume).

2、 Equipment installation and parameter setting

1. Installation and connection

1) Place the analyzer on a stable workbench and connect the power cable and data cable (such as USB or RS232 interface).

2) Install the sampling needle and secure it to ensure that the puncture depth matches the sample container, avoiding puncturing the bottom or top of the container.

3) Connect the pneumatic system and check the direction of pump operation and the smoothness of air flow.

2. Parameter initialization

1) Sampling time: Set according to the gas diffusion rate, usually 10-30 seconds, to ensure that the top gas fully enters the sensor.

2) Balance time: For samples that have just been sealed, they need to be left to stand for more than 30 minutes to allow the internal gas to reach equilibrium.

3) Pressure compensation: Adjust the sampling pressure to be consistent with the pressure inside the container to avoid gas leakage or backflow caused by pressure differences.

4) Detection mode: Select single gas detection (such as O?) or multi-component analysis (such as O?+CO?)? ）And set the alarm threshold.

3、 Calibration and Calibration

1. Zero point calibration

1) Rinse the gas path system with high-purity inert gas (such as N? Or Ar) to remove residual gas.

2) Place the sensor in a zero gas environment and perform a "zero calibration" operation to eliminate background noise.

2. Range calibration

1) Introduce a standard gas of known concentration (such as 10% O? Or 20% CO?) and adjust the instrument reading to the standard value.

2) Multi point calibration: For wide range detection (such as 0-100% CO?), at least 3 different concentration standard gases (such as 20%, 50%, 80%) need to be used for linear calibration.

3) Record the calibration coefficient and save it, and it will be automatically called up for subsequent testing.

3. Cross interference correction

If detecting multiple gases (such as the coexistence of O and CO), it is necessary to test the sensor's response to non target gases and compensate for interference through software algorithms.

4、 Sample testing and data validation

1. Testing process

1) Puncture sampling: Thread the sampling needle through the sealed lid of the sample container and extract the top gas to the sensor unit.

2) Data reading: Record the value after the reading stabilizes, repeat the measurement 3 times and take the average to reduce accidental errors.

3) Multi sample testing: When testing multiple samples continuously, it is necessary to blow the sampling needle with inert gas to avoid cross contamination.

2. Data validation

1) Parallel experiment: The same sample is divided into multiple containers for testing to verify the reproducibility of the data.

2) Comparison experiment: The deviation should be ≤ 5% when compared with chemical titration method (such as oxygen absorbent method) or third-party laboratory data.

3) Long term stability test: Run the instrument continuously for 8 hours to check if the sensor signal drift is within the allowable range (such as ± 2% F.S.).

5、 Common problems and solutions

1. Large fluctuations in readings

1) Reason: Poor sealing of the sample container, blocked gas path, or fluctuations in ambient temperature.

2) Solution: Check the sealing of the container, clean the air path filter, and strengthen environmental temperature control.

2. Calibration failed

1) Reason: Standard gas expiration, sensor aging, or zero drift.

2) Solution: Replace the standard gas, clean or replace the sensor, and re execute the calibration procedure.

3. Multi component detection error

1) Reason: Interference between gases or insufficient sensor selectivity.

2) Solution: Use high-precision sensors (such as NDIR infrared sensors) or add separation devices (such as chromatography columns).